Insulated slip-joint device



Dec. 22, 1953 R. M. sHlRK INSULATED SLIP-JOINT DEVICE Filed Nov. :50,1949 Gttorneg Patented Dec. 22, 19 53 t UNITED STATES PATENT OFFICEaeeasec INSULATED SLIP-JOINT DEVICE Robert M. Shirk, Wilmington, DeL,assigfior to Houdry' Process Corporation, Wilmington, Del.,acorporationof Delaware Application November 30, 1949, Serial No.130,129

' 9 Claims. I

This invention relates to an insulated slip-joint device for use inconnecting a pipe line to a vessel, and particularly to such use insystems reuuii'ing a long distance transfer of particulate solidmaterial at relatively high temperatures. More particularly, theinvention relates to an insulated slip-joint device adapted to connect atapered portion of an elongated pipe line to a vessel wall in suchmanner as to permit free longitudinal expansion or contraction of thepipe as" a result of severe temperature changes, while maintaining thejoint surfaces substantially free of particles of transferred solidmaterial and at lower ternperatures, in order to avoid serious abrasionof the slipping surfaces.

The invention, in general, is applicable to vari ous points ofconnection between vessels and conduits employed in the chemicalprocessing and petroleum refining arts. It is of particular ad vantage,for example, in connecting the gas=1ift pipe extending between the upperand the lower lift hoppers of a system such as that described in thearticle entitled l-Ioudri-flow: New Design in Catalytic Crackingappearing at page '78 of the January 13, 1949, issue of the Oil and GasJournal, or in connecting the catalysttransfer lines and vessels offluid catalytic cracking systems.

In such systems it is often necessary to pass pa ticulate solidmaterial, such as catalyst in grand lar or powdered form, in admixturewith gases or article. In the gas lift of that design, granularcatalyst, after passing downwardly as a n'iovin'g bed from an upper lifthopper through the treat ing or gas-solids contact section of thesystem,is

discharged into a lower lift hopper surrounding the lower end of thelift pipe, from which point, it is transported by means of a stream ofliftgas, which may be flue gas from the kiln of the treating section,through the vertical lift; pipe backinto the upper lift hopper tocomplete a cycle of catalyst flow. In present commercial practice inlarge scale units the lift pipe may be 150 to 250 feet in length and maybe maintained at temperatures: in the rangeof 850 to 1200' F.

In such ranges of pipe length and temperature the problem ofaccommodating differential expansion between the rigidly supportedvessels and their connecting conduits is obviously acute, and provisionmust be made for a possible expansion of 20-25 inches. While variousslip-joint devices are available in the art, none have been considered.suitable for use under severe conditions of temperature change andelongation, especially in an atmosphere of abrasive material, such asthe catalyst fines that may be found in there'gion surrounding the liftpipe in the upper lift hopper. The problem is accentuated when the'liftpipe is adapted to provide a gradual decrease in lift gas velocity, asbygradually' increasing its diameter In such case,

for an or a portion of its length. the opposed surfaces of a slip-jointhaving a cylindrical zone of contact would separate during a period orexpansion and tend to bind during a period of contraction. The presentinvention is especially effective in overcoming the diniculties arisingin the latter case.

In accordance with the invention, the longitudinal expansion andcontraction of the lift pipe i'saccomm'odat'ed by a packed joint, suchas" a stuffing-box, or any other suitable packing arrangement that willprovide a fluid-tight seal between the lift pipe and the" vessel wall. Asafeguardagainst deterioration of the joint packing by reason of thehigh temperatures to which the lift pipe and the vessel are subjected isobtained by the provisionof means for insulating the joint packing fromthe lift pipe and, if necessary, dissipat'ing a portion of the heat byindirect heat exchange with a fluid medium circulating through thecritical he'at zone. Injury to the contacting surfaces of theslip-joint, and the consequent destruction of the fluid seal, from theabrasive action of catalystlines or other foreign solidparticles-infiltrating into the joint from the interior' of the vesselis avoided by introducing gas, such as-steam, between the opposedslipping surfaces to f'ormacontinuous bleed into the vessel chambersufficient to clear the joint of such rereiga matter. If the lift pipeis to be tapered instead of cylindrical, the aiorelfientioneddisadvantage-of having opposed non-parallel join-t surfaces is obviatedby" constructing the men-- lat'ed c'ov'eri'n'g" surrounding the liftpipe the regionof the joint so that its outer maybe injected directlyinto the joint external source, or it may be introduce/J a medium iscirculated, in which case the lattli" p V v surface is; parallel to theaxis of movement. The bleed gas from an aeeacso serves the doublepurpose of exercising a temperature control and of flushing or cleaningthe joint.

For a fuller understanding of the invention ref erence may be had to thefollowing description and claims taken in connection with theaccompanying drawing forming a part of this application, in which:

Fig. l is a schematic view, in elevation, of a catalytic cracking systememploying a gas lift in which the present invention may be employed.

Fig. 2 is an enlarged sectional view of the slipjoint at the upper endof the lift pipe connecting it to the upper lift hopper,

Fig. 3 is a modification of the slip-joint showing the use of a fluidheat exchange medium on the vessel side of the joint; and

Fig. 4 is another modification of the slip-joint showing the use of afluid heat exchange medium on the lift pipe side of the joint.

Referring to Fig. 1 of the drawing, there is shown a schematicarrangement of a catalytic cracking system involving the cyclic flow ofgranular catalytic material between vertically spaced hoppers. Thecatalyst flows downwardly by gravity flow from the upper hopper througha treating section of the system to the lower hopper, and is returned tothe upper hopper by conveyance in a gas stream through a lift-pipesection of the system.

Summarizing, briefly, the description given in the cited article,catalyst is withdrawn from the bottom of the upper lift hopper H througha seal leg [2 which passes the catalyst downwardly into a combinedreactor-regenerator, generally indicated by the numeral it. The catalystpasses by gravity flow in a moving bed downwardly through the vessel i3,and is withdrawn in regenerated condition from the bottom thereofthrough a seal leg M which passes the catalyst downwardly into the lowerlift hopper 15. A vertical lift pipe l6, preferably tapered to provideincreased flow area at its upper end, connects the upper and lower lifthoppers ll and I5, respectively. A continuous stream of lift gas isintroduced into an engagement zon within the lower lift hopper 15, asthrough inlet H, wherein the catalyst is engaged by the lift gas andconveyed upwardly through the lift pipe l6 into the upper lift hopperII, the catalyst being separated from the lift gas in the upper hopperand subsequently recycled through the system. For the purposes ofillustration, the lift gas is shown as being supplied to the inlet lineH from the flue line l8 which receives flue gas from the regeneratorsection of the vessel [3 through outlets [9. It is to be understood,however, that other means for introducing lift gas into the lower lifthopper, and other lift gases, such as air, steam, hydrocarbons etc. maybe employed as the lift medium.

In view of the length of lift pipe required in large-scale commercialoperations, and of the high temperatures commonly employed, allowancemust be made in the system for longitudinal expansion and contraction ofthe catalyst transfer lines. The lift pipe extends between hoppers whichare fixedly supported on a rigid framework, and is therefore subject toa considerable amount of elongation and contraction. While accommodationfor the variations in lift pipe length may be made at either end of thelift pipe or at some intermediate point, a preferred arrangement is toprovide for such expansion and contraction at the oint where the upperend of the lift pipe enters the upper lift hopper. Because of the scaleto which the schematic illustration is drawn, it has not been possibleto show any details of the slip-joint in the lower conical head ofhopper H in Fig. 1. A detailed illustration of the slipjoint and itsassociation with the hopper II and the lift pipe i6 is clearly shown inthe sectional view of Fig. 2.

Referring to Fig. 2, the fragmentary lower conical portion of hopper l Iis shown as terminating in a short cylindrical neck portion 21, providinan opening in the lower end of the hopper of substantially greaterdiameter than the diameter f the upper end of the lift pipe it. Aflanged stuffing-box housing 22 extends within the opening in the lowerend of hopper ii and is secured, as by welding, to the neck portion 2!.The lift pipe 86 passes centrally through the housing 22 and terminateswell within the upper lift hopper. The portion of lift pipe l8 adjacentto and passing through the hopper opening is provided with a skirt-likesleeve member 23 turned inwardly at its upper end and rigidly secured tothe outer surface of the lift pipe. The sleeve 23 is cylindrical inshape and is arranged so that its axis is coincident with the axes oflift pipe it and the stuffing-box housing 22.

The annular space between the cylindrical sleeve 23 and the tapered liftpipe i6 is filled with a suitable insulating material 24, so that,despite the high temperature of the lift pipe, the outer surfaces ofsleeve 23 may be maintained at a temperature that will not be injuriousto the packing material used in providing a fluid-tight seal in theslip-joint. A flat ring member 25 is secured to the upper end of housing22, surrounding the sleeve 23 and substantially closing one end of theannular space formed between the housing and the sleeve. The opening inring 25 is slightly larger than the sleeve 23, so that the latter maymove freely through the opening. A ring member 26 is secured to theinner wall of housing 22 to divide the annular space between the housingand the sleeve into an upper chamber 21, into which steam may beintroduced through inlet 28, and a lower chamber 29 for receiving thejoint packing 3!). Ring member 26 is slightly larger than the sleeve 23,so that the latter may move freely through the ring. A packing gland 3ifits within the open lower end of housing 22, both members bein providedwith the usual flanges and flange bolts 32 for compressing the jointpacking 3G sufficiently to obtain the necessary seal.

Because of the accumulation of granular catalyst in the lower portion ofhopper H, and especially an accumulation of minute particles or fineswhich are unavoidably produced by attrition as a result of continuouslycirculating the catalyst through the system, there is a tendency for thefine catalyst particles to infiltrate into the joint. The fine solidparticles are injurious, to the opposed joint surfaces, eventuallydestroying the fluid-tight seal. By introducing a gas, such as steam,which is compatible with the gas or vapor within the hopper l I, intothe chamber 27 at a rate sufficient to provide a constant bleed into thehopper through the space between the sleeve 23 and the ring 2%, catalystmay be prevented from entering the joint. Thus, the outer surface ofsleeve 23 in the region immediately adjacent the joint packin ismaintained in relatively clean condition, so that catalyst particles areprevented from clinging to the surface of the sleeve and being carriedduring periods of contraction between the sealing surfaces of the sleeveaccessed 23 and the packing to. In addition to. its function ofpreventing catalyst infiltration into the joint, the gas chamber 21 mayserve the additional useful function of carrying oilv heat from thesleeve 23 by direct heat exchange with the fluid heat exchange mediumpassing through the chamber 2?.

Referring to 3 of the drawing, a modified form of sleeve joint isillustrated. The portion of lift pipe is passing through the opening. inneck 2! of hopper ii is covered by a cylindrical sleeve member 33 ofsubstantially larger diameter than the diameter of the lift pipe. Thecylindrical member 33 is turned inwardly at its upper and lower ends 34and 35, respectively, to form a confined space between the lift pipe andthe sleeve for the reception of suitable insulating material 35 havingsunlcient insulating properties to maintain the outer surface of thesleeve 33 within a safe temperature range. An annular member ofirregular shape is attached to the underside of hopper ll surroundingthe sleeve member 33. The irregularly-shaped member comprises acylindrical wall section 3? attached at its upper end to the slopingbottom of the upper lift hopper and depending therefrom concentricallyto the neck portion 25. The lower end of cylindrical member 3'! isturned radially inwardly at 33 and then upwardly at 39 to form a shortcylindrical portion terminating at its upper end in a concave annularportion is adapted to receive a packing ring ll. The annular memberformed by the portions 31, 38 3e and it provides a chamber 52surrounding the slipjoint. An inlet 33 in the. cylindrical wall 31 ofthechamber 332 is provided for the introduction of gas, such as steam,into the annular chamber. The upper end of the concave portion 48 isspaced slightly from the'lower end of neck 25, so as to provide acircumferential gas outlet from the chamber 42 into the space betweenthe neck portion El and the cylindrical sleeve portion 33. The gasintroduced through inlet 43 functions in the same manner as gasintroduced through inlet 28 of Fig. 2.

Referring to Fig. 4 of the drawing, the sleeve member of Fig. 3 is shownin modified form. In order to provide increased capacity for heattransfer away from the region of the slip-joint, a cooling coil id isembedded in the insulation material 36 surrounding the lift pipe it,through which a fluid coolant is continuously circulated. In Fig. i, theshielded portion of the lift pipe is shown as passing through a fiathorizontal wall member ie of a vessel, in order to show its applicationto vessel walls of different configuration. The opening in wall memberas is large enough to permit free longitudinal movement of thecylindrical portion 33 of the sleeve. A flanged neck 56 is attached tothe undersurface of wall 45 concentric to the opening therein, thediameter of the neck 46 being substantially greater than the diameter ofsleeve member 33 in order to provide a suitable space therebetween toform a stuffing-box. An inlet 47, for steam or other gas, is provided inthe side of neck 65 near its upper end to permit the introduction of astream of gas into the annular space between the neck 65 and thecylindrical sleeve member 33, so that a constant bleed may be maintainedthrough the space between the sleeve member and the vessel wall 45.Within the stufling-box formed by the member 46 there is first placed alantern ring 48 followed by layers of packing t9. Packing gland 58compresses the packing material 49 by means of bolts il in a"conventional manner so as to provide a fluidtight slip-joint for thesleeve member 33'. The lantern ring 48 spaces the packing material. 49'from the base of the stufiing-box sufficiently to permit uninterrupted.introduction of gas through inletd'l.

It is obvious that the invention is susceptible to various othermodifications without departing from the spirit or essential attributesof the invention.

What is claimed is:

1. A slip-joint between a vessel wall and a tapered portion adjacent tothe free end of an elongated conduit extending through an open ing insaid wall, and adapted to maintain asealed connection therebetween whilepermitting substantial relative displacement longitudinally of the axisof said conduit as a result of extreme changes in temperature,comprising a spaced sleeve member concentrically encircling said taperedportion and extending therewith through said opening, said sleeve memberhaving a cylindrical outer surface, heat-resistant means betweensaid'sleeve member and said conduit, a housing member secured at one endalong the edge of said opening and extending outwardly from said wall,said housing member being radially spaced from and encircling anintermediat portion of said sleeve member, a packing between saidhousing member and said sleeve member adapted to provide a fluid-tightslip joint therebetween, means for retaining said packing inwardly fromthe supported end of said housing member, and means for introducing afluid medium into the annular space formed between the inner portion ofsaid housing member and said sleeve member for passage into said vesselthrough said opening.

2. A slip-joint as defined in claim 1 in which said sleeve membercomprises a cylindrical mem ber of substantially greater diameter thanthe maximum diameter of the encircled portion of said conduit, and aninsulating material filling the annular space between said cylindricalsleeve member and said conduit.

3 A slip-joint as defined in claim 2 including a pipe coilconcentrically embedded within said insulating material for continuouslycirculating therethrough a iiuid heat exchange medium.

4. A slip-joint as defined in claim 1 in which the inner end of saidannular chamber formed between said housing member and said sleevemember is substantially closed, so as to provide a free sliding fit withsaid cylindrical outer surface of-said sleeve member.

5. A slip-joint as defined in claim 4 in which said cylindrical sleeveis of greater diameter than the maximum diameter of the encircledportion of said tapered conduit, and including an insulating materialfilling the annular space between said cylindrical sleeve member andsaid tapered conduit, and means for compressing said packing to maintainsaid fluid-tight slip-joint.

6. A slip-joint between a vessel wall and a tapered portion adjacent tothe free end of an elongated conduit extending through an opening insaid wall, and adapted to maintain a sealed connection therebetweenwhile permitting substantial relative displacement longitudinally of theaxis of said conduit as a result of extreme changes in temperature,comprising a spaced sleeve member concentrically encirclin said taperedportion and extending therewith through said opening, said sleeve memberhaving a cylindrical outer surface, heat-resistant means between saidsleeve member and said conduit, a stuffing box member surrounding saidsleeve member and extending partially within said opening, saidstuifing-box member being secured to said vessel wall around saidopening, and having inwardly-extending radial members both at the innerend and at a point intermediate the ends thereof forming, respectively,an end closure and an internal partition, said partition dividing saidstuffing-box into inner and outer chambers, said closure member and saidpartition member forming a free-slidin fit with the outer surface ofsaid sleeve member, a packing in the outer chamber of said stuffing-boxmember, a packing gland in the outer end of said stuffing-box adaptedwith said partition member to compress said packing and form afluid-tight slip-joint around said sleeve member, and means forintroducing a fluid medium into the inner chamber of said stuffing-boxfor passage into said vessel through said opening.

7 7. A slip-joint between a vessel wall and a tapered portion adjacentto the free end of an elongated conduit extending through an opening insaid wall, and adapted to maintain a sealed connection therebetweenwhile permitting substantial relative displacement longitudinally of theaxis of said conduit as a result of extreme changes in temperature,comprising a spaced sleeve member concentrically encircling said taperedportion and extending therewith through said opening, said sleeve memberhaving a cylindrical outer surface, heat-resistant means between said,sleeve member and said conduit, an annular housing member ofsubstantially U- shaped cross section secured along its upper outsideedge to the outer surface of said vessel about and spaced from saidopening, the inner side wall of said annular housing member beingcircumferentially indented to form a packing-ring groove, the upper edgeof said inner side wall of said annular housing member being spaced fromthe vessel wall about the edge of said opening to form a circumferentialpassage between the annular chamber formed within said annular housingmember, a packing-ring in said packingring groove forming a fluid-tightslip-joint between said housing member and said sleeve memher, and meansfor introducing a fluid medium into said annular chamber, said fluidmedium passing through said circumferential passage and through theannular space between the edge of said opening and the surface of saidsleeve memher into said vessel.

8. A slip-joint between a vessel wall and a tapered portion adjacent tothe free end of an elongated conduit extendin through said wall, andadapted to maintain a sealed connection therebetween while permittingsubstantial relative displacement longitudinally of the axis of saidconduit as a result of extreme changes in temperature, comprising aspaced sleeve member concentrically encircling said tapered portion andextending therewith through said opening, said sleeve member having acylindrical outer surface, insulating material in the space between saidsleeve member and said conduit, a stuihngbox member surrounding saidsleeve member and secured at one end to the outer wall surface of saidvessel inwardly from the edge of said opening, a lantern-ring in thebase of said stuffingbox adjacent to said vessel wall, a packingoutwardly adjacent said lantern-ring, a packinggland for compressingsaid packing against said lantern-ring to form a fluid-tight slip-jointaround said sleeve member, and means for introducing a fluid medium intothe base of said standing-box adjacent said lantern-ring for passageinto said vessel through the annular space formed between the edge ofsaid opening and the outer surface of said sleeve member.

9. A slip-joint as defined in claim 8 including means for circulating afluid heat-exchange medium Wholly within said insulating material and inindirect heat-exchange therewith.

ROBERT M. SHIRE.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,103,981 Hall Dec. 28, 1937 2,407,700 I-Iufi Sept. 17, 19462,438,312 Bunn et al Mar. 23, 1948 2,444,211 Wager June 29, 194:82,457,232 Hengstebeck Dec. 28, 1948 2,517,083 Carlson Aug. 1, 1950

